Your wafer is most likely not clean. If you are talking about wafer coming
out of a brand new box, they are probably in the worst shape. You should do
at least a solvent clean if not Piranha clean.

The other possibility is that the Cr is so high stress (which is very
likely) that the additional DI surface tension was able to delaminate the
Cr/Si interface. I have had delayed reeling due to stress relaxation, and
most of the time the failure point is the Cr/Si interface.

Good luck.

Henry



Soojin Oh @memsnet.org on 04/09/2002 09:10:54 AM

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Subject:    [mems-talk] 3000A Cr by thermal evaporation?



3000A Cr was deposited by thermal evaporation on top
of SiO2 surface, and kept on table top for 3 month. Cr
layer peels off when DI water is squirted onto the
surface from wherever water touches. Can you suggest
any possible causes? Contact surface was supposedly
clean because I handed new clean wafers to this person
who did evaporation, but I don't know what kind of
effort was made to clean them further. Cr layer was ok
right after deposition, 3 month ago.
Thank you.

-Soojin
Yahoo! Tax Center - online filing with TurboTax
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